Nicola, F. 2009. On the absence of the one-sided Poincaré lemma in Cauchy-Riemann manifolds. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE. 4, 4 (Dec. 2009), 587-600. DOI:https://doi.org/10.2422/2036-2145.2005.4.02.